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Beginnings of a new Bonneville Cutthroat Trout population

Beginnings of a new Bonneville Cutthroat Trout population

Bonneville Cutthroat Trout
DWR biologists plan to stock Diamond Fork with Bonneville Cutthroat Trout.
(Photo by Scott Root)

August 21, 2006

UTAH COUNTY - Bonneville cutthroat trout, a fish that once thrived in Utah, will soon be swimming in another river in the state.

On Aug. 16, biologists with the Division of Wildlife Resources, in cooperation with the U.S. Forest Service, treated approximately 21 miles of stream in the upper stretches of the Diamond Fork river drainage with rotenone.

Most of the fish in the 21-mile stretch are brown trout, and the rotenone should remove all of them.

Initial results show the Aug. 16 treatment was a success. Biologists will treat the area again on Sept. 20. The treatment area begins about 10 miles from the mouth of Diamond Fork Canyon, at the Three Forks area, and continues upstream to its headwaters.

Biologists are removing fish so native Bonneville cutthroat trout can be placed in the river. Restoring Bonneville cutthroat trout to their historic range in Utah is an important step towards keeping this sensitive species off the Endangered Species List and ensuring the future health of the species. The project will also provide great fishing for anglers.

Applying rotenone in Diamond Fork river
DWR employee Casey Riches applies rotenone with a backpack sprayer.
(Photo by Scott Root)

DWR biologists have taken eggs from spawning Bonneville cutthroat trout in Mountain Dell and Little Dell reservoirs east of Salt Lake City over the past year. This egg-taking effort provided them with enough fish for the Diamond Fork project.

The U.S. Forest Service has also contributed to the project's success by installing a fish barrier at Three Forks. The barrier will keep the brown trout in the 10-mile stretch below the project area separate from the Bonneville cutthroat trout population the biologists are establishing.

A Big Effort

Rotenone was administered to the water via drip barrels that were placed in 20 locations. Biologists also used backpack sprayers to apply rotenone to areas that were difficult to reach. After the treatment, biologists applied an oxidizing agent, potassium permanganate, to the end of the project area (near Three Forks) to neutralize the effects of the rotenone.

Once all of the fish have been removed, the DWR will stock the project area with 10,000 three-inch Bonneville cutthroat trout. The area from Three Forks and upstream will be closed to fishing in 2007 to allow these small cutthroats to grow.

"Several streams are tied to the main stem of the Diamond Fork River. These streams aren't separated from the river by any barriers, so placing fish in the river will allow us to restore Bonneville cutthroat trout to several drainages at the same time," says Don Wiley, the DWR regional aquatics manager who coordinated the project.

"Also, the cutthroat trout in the main stem of Diamond Fork can access those tributaries during the spawn, or any time of the year, which will help maintain a gene flow throughout the cutthroat trout population in the area."

The DWR is conducting the project with support from the U.S. Forest Service, the Central Region Advisory Council, the Governor's Office of Planning and Budget Resource Development Coordinating Committee (RDCC), Trout Unlimited, the Blue Ribbon Fisheries Council and other organizations.